Improvement in cast-iron boilers



UNITED STATES PATENT OFFICE.

JOSEPH A. MILLER, OF NEW YORK, N. Y.

Specification forming part of Letters Patent No. 50,611, dated October 24, 1865.

To all whom it may concern:

Be it known that I, J. A. MILLER, of the city, county, and State of New York. have invented a new and useful Improvement in Steam- Boilers; and I do hereby declare that the following is a full, clear, and exact description thereof, which will enable those skilled in the art to make and use the same7 reference being` had to the accompanying drawings, forming part of this specification, in which- Figure l represents a longitudinal vertical central section of this invention. Fig. 2 is a transverse vertical section of the same, the line m00, Fig.l, indicating the plane of section. Fig. 3 is a similar section taken in the Plane indicated by the line y y, Fig. 1.

Similar letters of reference indicate corresponding parts.

rllhis invention consists in constructing the fire-box of a steam-boiler and also the boilerlues ofcast-iron strengthened by ribs or anges projecting into the interior of said fire-box or lue, and also into the surrounding water-space. The fire-box is also cast with pins projecting inside and outside, wherebythe heat-conducting power of said fire-box isincreased; and such pins may or may not be cast on the flue. rI he ribs or iianges have a spiral or partiallyspiral direction around the axis of the flue, and they diminish in the interior of the fiue toward the bottom thereof, lea-ving that part smooth for the purpose of facilitating the removal of soot and ashes.

A represents a steam-boiler, the fire-box B of which is constructed of cast-iron, strengthcned by ribs or iianges which project in the surrounding waterspace, and also into the in terior re-space of the re-box. These ribs not only serve to strengthen the fire-box, but they also materially increase the heat-conducting power of the same. The spaces between the flanges or ribs are or may be occupied by a series of pin s, a, projecting inside and outside, as clearly shown in the drawings. The object of these pins is to increase the heatconducted through the cast-iron plates, and they are cast solid with the saine so that they are easily made and the cost of the plates is not much increased. rIhe flue O is also made of castiron and provided with ribs or iianges c, which project on the inside and outside, the same as those on the fire-box. 1f desired, the spaces between these anges may be illed up with heat-conducting pins. The ribs on the fire-box and on the flue extend in a spiralor partiallyspiral direction, and those in the interior of the flue diminish toward the bottom thereof, leaving the sanie smooth, so as to facilitate the removal of dirt, ashes, and soot. Nicks d, cast into the ribs at certain intervals, allow them to expand and contract freely by the heat and prevent injury by sudden or unequal expansion.

rEhe advantages of this arrangement are manifold. In therst place, careful experiments of eminent philosophers, such as Peclet, have.

established the fact that the heat-conducting power of cast-iron in proportion to that of wrought-iron is as sixty-six to thirty-nine, or, in other words, if the heat-conducting power of clay is one, that of wrought-iron is thirtynine, and that of cast-iron sixt '-six. By the ribs and pins the heating-surface of the boiler is materially increased, and the whole available heat can be conveyed into the water in a shorter boiler with less tlues than thosemade of smooth wrought-iron plates, and thus the cost of the boiler and its size are reduced, the latter item being of peculiar value Vfor vessels of war, because it allows of placing the boiler below the water-line.

For ordinary steamships I place a series of egg-shaped iiues above the crown-sheet of the fire-box, giving to the water free access to all parts ot' the external surface of the tire-box and lines. By the spiral form of the ribs the circulation of the water is facilitated and the formation of incrustation is avoided.

It is obvious that these improvements are applicable to locomotive and stationary steam- I claim as new and desire to secure Letters 3. The ueO,wth oblique taperingribs form Patenting a portion thereof, as and for the purposes 1. The re-box B, with ribs or flanges b prospeoied. jeetingnwardly and outwardly therefrom, substantially as set forth.

2. The conducting-pins et a, projecting in- Witnesses: wardly and outwardly from the shell of' the M. M. LIVINGSTON, fire box or ue,substantiall y as set forth. G. L. TOPLIFF.

JOSEPH A. MILLER. 

